Although he had no idea at the time, Mr Barry believes his first exposure to mould began when his family moved into a home in Balgowlah, on Sydney’s northern beaches. It was where he spent all of his teenage years.

“A lot of the symptoms I had at that time are now what I correlate to mould exposure. The house itself had very high humidity. We had DampRids filling up in no time. Mould would grow on clothes very quickly and there was just a lot of superficial mould in the bathroom,” he said.

Mr Barry became ill when he was a teen, and at 17 was diagnosed with chronic fatigue syndrome. (Supplied)

Later, there would be more diagnoses from a specialist in chronic illnesses - myalgic encephalomyelitis (ME) and also multiple chemical sensitivity (MCS).

But despite doing his best to follow the advice of his specialist on how to manage the illnesses, Mr Barry’s health continued to decline.

For many years, Mr Barry said he simply did his best to muddle through.

“I had a fallacy that being young and athletic meant I would wake up one day and everything would be fine. And essentially I just tried the mind-over-matter approach for many years, to no effect.”

Then, five years ago, Mr Barry moved into an apartment in Bondi and his health took another turn for the worse.

“I began to get really intense neurological symptoms. I could barely talk. I was stammering. I was fully housebound. I couldn’t walk to the end of my street. My brain shut down. I literally couldn’t remember what year it was.”

Like the house in Balgowlah, the Bondi apartment was also riddled with mould, he said.

“When I lived in Bondi, the entire time I was there, there was black mould which had begun to sprawl across my bathroom ceiling.”

It wasn’t until Mr Barry moved down to Woodend in Victoria to live with his father that he had any relief from the debilitating symptoms.

“Moving caused a revolution in my health overnight. I went from chronic insomnia, not being able to sleep at all, night upon night, and overnight I got down there and I began sleeping perfectly.

“My energy instantly picked up and I began going for walks.”

Chronic illness and living the life of a mould avoider can be an isolating experience, Mr Barry says. (Supplied)

The possibility that mould could be behind his ill health had long been a “niggling thought” at the back of his mind, Mr Barry said.

“I had come across mould online and in a few groups where people believed that mould is the underlying cause of CFS, Lyme disease and a bunch of illnesses, which I found really far-fetched and outlandish.

“I had come across that sentiment for years and I just completely neglected it. I thought these people have lost it.”

But Mr Barry began to explore the idea further, avoiding mould where he could and seeing a vast improvement in his health, despite the home he was living in not being completely mould-free.

Then Mr Barry stayed in a friend’s storm-damaged and mouldy caravan for a weekend and became severely ill. It was enough to convince him drastic action was needed.

So began the path to extreme mould avoidance. Mr Barry started getting rid of all his possessions and bought a new tent.

‘It was immediate. My brain felt clear.’

The first night he slept in his tent confirmed had had made the right decision, Mr Barry said.

“That first night was the most profound shift in my health that I have had in seven years. It was immediate. My brain felt clear and I had word recollection immediately.”

In late October, Matt Walsh moved into a van he had stripped and refitted with materials he would not react to. (Supplied)

Like many mould avoiders, Mr Barry follows the strict protocols of Lisa Petrison, a US academic and myalgic encephalomyelitis (ME) sufferer, and Erik Johnson, a former US soldier who re-purposed the decontamination protocol for warfare and applied it to mould.

The pair’s Facebook page has 11,000 followers and they have co-authored a beginner’s manual for mould avoidance.

The advice includes physically washing off the mould with a shower after any accidental exposure, something Mr Barry admits he also found “outlandish” at first but now follows religiously.

“I figured I would give it a shot and it has actually become one of the most powerful tools I use. If I walk into a bad building the symptoms gain intensity and get exponentially worse unless I wash.”

Sometimes, just speaking to a person who lived in a mouldy environment could be as bad as going into a building with mould, Mr Barry said.

“If you live in mould or you drive a mouldy car, which to be honest most people do, my body will respond in the same way as going into a shop.

“When I am with people on the mouldier end of the spectrum my brain completely shuts down, I start to get neurological symptoms and I can’t talk properly.

“It’s hard because when I feel mould initially it’s a really intense feeling and it’s kind of hard not to let that be known. I probably appear quite startled at times.”

While Mr Barry says he has no regrets about the time he has spent on the road, the lifestyle can be lonely.

“To be chronically ill in bricks and mortar is one thing, but then to be chronically ill and out in the wilderness alone it really compounds the isolation.”

National inquiry puts focus on mould

While mainstream medicine is at pains to point out that there is not enough evidence to link mould exposure to chronic immune illnesses such as CFS and ME or the severe neurological symptoms many say they suffer from, attention on the biotoxin is growing.

A recent Federal Government inquiry into mould-related illnesses received more than 100 submissions from Australians who said they were suffering from debilitating symptoms as a result of mould and had failed for many years to find doctors who would listen to them.

The bipartisan inquiry’s final report called for the government to fund research into the health impacts of mould and develop guidelines for doctors.

Some doctors are also beginning to speak out about the large numbers of people who could be experiencing ill health as a result of biotoxins, mould being the most common.

“I would certainly say it’s a hidden problem. It’s happening much more than we expect or know, and it’s definitely devastating and debilitating for the people who get it,” NSW Central Coast doctor Christabelle Yeoh told nine.com.au earlier this year.

Chronic fatigue was “a classic diagnosis” for someone who may be experiencing problems related to mould exposure, Dr Yeoh said.

“Where the cause isn’t found they might be given antidepressants. Or they might just be told to exercise more and get on with their life better but they try yet they can’t get over the hump.”

“Another common thing is where people’s brains just don’t work well on a functional level so they will think that they are even getting early dementia.”

Chasing wellness in a van

Former IT sales executive Matt Walsh is another mould avoider.

He fell ill seven years ago and saw specialist after specialist before being diagnosed with many of the same chronic illnesses as Mr Barry - Chronic Fatigue Syndrome (CFS), Multiple Chemical Sensitivity (MCS) and Chronic Inflammatory response syndrome (CIRS).

In January, a doctor finally identified mould exposure as being the trigger for his illnesses.

As well as mould, Mr Walsh is acutely sensitive to several types of pollen and chemicals used in food and building materials.

His failing health forced him to quit his job and move down to his brother-in-law’s place in Jervis Bay, where he camped outside for six months.

The tent Matt Walsh slept in for six months, including during winter, in his brother-in-laws Jervis Bay backyard. (Supplied)

Out of desperation, Mr Walsh started an online fundraiser which helped raise $22,000 for him to refit a van for him to live in.

The van was stripped back to bare metal before being fitted with insulation and materials Mr Walsh does not react to.

His new mobile home, which he moved into earlier this month, is solar powered and kitted out with a functional sleeping area and kitchen.

So far life on the road had thrown up its challenges, he said.

After initially driving up to Brisbane, Mr Walsh had been forced to change his location several times to avoid winds bringing pollen.

“Anything that’s outside the van, in the air, comes in, so it’s not like being in a house where you are quite sealed in. For me the biological stuff, the pollen, can be worse than the chemicals,” he said.

Matt Walsh and a picture of the inside of his van. (Supplied)

Soon, Mr Walsh will travel inland, to outback Queensland or NSW, where there is less chance of coming across the pollen that makes him so ill.

Mr Walsh admits he has no certainty about whether his new extreme lifestyle will be successful in stabilising his health.

“There is enough conjecture out there from mainstream doctors for me not to be totally positive that this will work. But then there are people who have been really sick and have gotten better.

“If it doesn’t work I am trying to gain quality of life. With the van I can go and see a bit of Australia and spend some time in nature and get some sunshine.

“If that is as good as it gets then that’s what I’ve got to live with. Being stuck inside sick is not a life.”